PROJECT SUMMARY/ABSTRACT Population Research and Methods Core (RC-PRM) The Population Research and Methods Core (RC-PRM) employs a multi-pronged approach to support Mount Sinai Older American Independence Center (MS-OAIC) investigators confronted with methodological and analytic issues that occur in the study of older adults with Alzheimer?s Disease and Related Dementias (ADRD) and other serious illness. This core has been highly productive in providing support for numerous OAIC investigators through our research consultancy program, research methods training program, and mentoring, all with an over-arching theme of supporting population-based research. For this application, we have assembled a cadre of experts, some who have served as past consultants and some who are new, with a broad range of knowledge and expertise to serve as potential consultants to investigators. We have added new initiatives to support dementia research including collaboration with consultants who are leaders in dementia research, and new training modules focusing on capacity for consent, instrument selection, subject retention, caregiving measures and outcomes, and longitudinal analysis of cohorts with ADRD. We have expanded our training for both faculty and master?s trained analytic staff, focusing on observational research methods, and have added new training and support in implementation science. Resources and expertise will be provided in a variety of ways and throughout all phases of the research process - from study design to interpretation and presentation of findings. The RC-PRM will provide analytic support for four proposed pilot and exploratory studies and one external project, each of which address the research goals of the OAIC. In addition, RC-PRM will conduct a developmental project employing latent class growth modeling to explore burdensome treatment trajectories for those with ADRD laying the foundation for future work exploring the intersection of dementia, function, and multimorbidity on burdensome treatments from dementia diagnosis to death. The RC-PRM specific aims are: 1) To provide rigorous methodological and analytic support to OAIC investigators; 2) To apply advanced research and statistical methodology (e.g., latent class analysis, propensity scores, instrumental variable estimation, competing risk analysis) used in other fields but not commonly applied to aging-related research; 3) To collaborate closely with the REC and PESC to ensure that junior faculty obtain research methods training to advance their current knowledge and expertise and to promote their independence; 4) To develop infrastructure for population-based research through faculty and analytic staff training specific to population-based research methods; and 5) To expand our consultancy program and research methods training to the areas of dementia and implementation science. Through consultations with experts on a range of topics addressing the methodological and statistical issues encountered in the study of seriously ill older adults and the development of research infrastructure, this Core aims to advance the rigor of geriatric palliative care research and support future geriatric palliative care research endeavors.